<!DOCTYPE HTML>
<style type="text/css">
html, body { margin: 0; padding: 0; border: none; }
</style>

<div style="position: absolute; width: 200px; height: 400px; top: 100px; left: 100px; box-shadow: 0 0 14px blue">A</div>
<div style="position: absolute; width: 100px; height: 400px; top: 100px; left: 400px; box-shadow: 0 0 14px blue">B</div>
